Astronomers spot incredibly rare, insanely explosive pair of stars

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Astronomers at the ESO (the European Southern Observatory) have announced an astonishingly unusual find: A pair of double stars, dubbed VFTS 352, roughly 160,000 light years away in the Tarantula Nebula. The Tarantula Nebula already holds multiple records — it’s the most active starburst region in the Local Group of galaxies (meaning it is churning out new stars at a very high rate), and it’s already so bright, it would cast shadows on Earth if it were as close to us as the Orion Nebula (a stone’s throw away, at just 1,344 light years). Even given these feats, a double star stands out.

You’ve probably heard of binary or even trinary star systems, in which multiple stars orbit each other in a stable configuration. In some cases, binary stars orbit close enough to each other that their gaseous envelopes touch, in what is sometimes called a contact binary. This configuration, in contrast, is what astronomers call an “overcontact binary,” and what the rest of the world refers to as a “stellar strapless bra.”

A really big strapless bra. With surface temperatures that exceed 40,000C, a combined mass 57 times larger than our sun, and each crazily rotating around the…

Ok, we’re going to need to drop the metaphor at this point. Just imagine two hyperactive, unstable stars that are separated by a mere eyeblink (in stellar terms, 12 million kilometers ain’t squat). Each is classified as an O-type star — and O-type stars are the rarest main sequence stars in the universe, comprising just 0.00003% of known stars. They’re extremely prone to going supernova and collapsing into black holes or neutron stars. Finding two of them 12 million kilometers apart and actively merging, therefore, is something of a treat.

That’s an O-type star in comparison to the other main sequence stars. Our sun, in contrast, is a G-type main sequence star.

Right now, the stars of VFTS 352 are estimated to be sharing roughly 30% of their total mass between each other. No other overcontact binary is known to be this large or to share that great a percentage of its mass. According to the ESO, “The VFTS 352 is the best case yet found for a hot and massive double star that may show this kind of internal mixing,” explains lead author Leonardo A. Almeida of the University of São Paulo, Brazil. “As such it’s a fascinating and important discovery.”

Right now, astronomers are predicting the star will die in one of two ways. Either the two stars will merge, forming a single giant and insanely unstable O-type star (possibly a hypergiant) before collapsing into a long-duration gamma ray burst (and incidentally, likely sterilizing every single planet within a non-trivial distance). Option #2 is explained by Selma de Mink of University of Amsterdam: “If the stars are mixed well enough, they both remain compact and the VFTS 352 system may avoid merging. This would lead the objects down a new evolutionary path that is completely different from classic stellar evolution predictions. In the case of VFTS 352, the components would likely end their lives in supernova explosions, forming a close binary system of black holes. Such a remarkable object would be an intense source of gravitational waves.”

Be glad our corner of the Milky Way is relatively boring. Remarkable objects like VFTS 352 are capable of causing extinction events across galactic distances. As Wikipedia notes: ” GRB [Gamma Ray Burst] 080319B, for example, was accompanied by an optical counterpart that peaked at a visible magnitude of 5.8,comparable to that of the dimmest naked-eye stars despite the burst’s distance of 7.5 billion light years. Assuming the gamma-ray explosion to be spherical, the energy output of GRB 080319B would be within a factor of two of the rest-mass energy of the Sun (the energy which would be released were the Sun to be converted entirely into radiation).

Be back later. I need to stock up on sunscreen.

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“…before collapsing into a long-duration gamma ray burst (and incidentally, likely sterilizing every single planet within a non-trivial distance)”
Can someone explain me the above? sterilizing every single planet ? what does it mean? is the milky way withing a trivial or non trivial distance?

The last paragraph seems to explain what the gamma ray burst would likely do but I didn’t get the gist of it? dimmest naked-eys stars despite…and so on..
can someone explain the last paragraph too?

Thank you

Joel Hruska

Think of a gamma ray burst like a deadly pencil of destruction. It can kill anything it hits for miles, but it’s narrow and highly focused. It also loses power with range.

A major GRB aimed at Earth from a dozen light-years away would destroy all life on the planet.

David

In other words: When the aliens don’t want us around anymore, they’ve got something to work with besides a direct assault.

Don’t worry about it. In order to hit the Earth, or even our Solar system, the axis of the star would have to be pointed directly at us. I don’t know of any suitable stars in the trivial distance range that could be used for that purpose. Plus, if they could move the axis of rotation of a star, they’d already have the capability to wipe us out without having to use a GRB.

The last paragraph is just to illustrate the potential power of a gamma ray burst, noting that one such burst could still be seen with a reasonable amount of brightness from 7.5 billion light years away, so you can imagine what it was like for its originating galaxy. Such things likely play a role in the Fermi paradox.

I think you mean ‘trivial’, though that’s not really a good use for the word.

MrBK

Actually 160,000 light years is within our own galaxy, and given that such gamma rays burst would be capable of causing “extinction events across galactic distances” , this is something to worry about.

Lorfa

It’s not within our own galaxy, it’s in the Large Magellanic Cloud.

It’s not worrisome because most objects emitting gamma ray bursts do not do so at the level of intensity as for example GRB080319B. They also do not point directly towards us, again like GRB080319B.

It’s also not clear that VFTS 352 will end its life that way, it may become a binary black hole system. Lastly it may be a very long time before VFTS 352 goes EOL.

Joel Hruska

While our galaxy is approximately 100,000 LY across, the Large Magellanic Cloud is only about 160,000 LY away.

MrBK

Yes indeed thanks, I got confused by one order of magnitude :)

bob lebart

If I owned my own Galaxy, I would keep a couple of these for pets.

random_name

Thank you for my morning laugh.

Talesin

Indeed! Name them Kodo and Podo.

DaMadOne

Once those stars dissipate (lack of a better word), we will catch a glimpse of Goku and Gohan

Included in my Christmas list this year will be a wish for people to stop using this stupid/pretentious term “non-trivial” when there are so many others that are either simpler or contain more information or both. In this instance I would have used “within light years” or “within several light years”. More information, less awkward. Overall a fascinating article though. I wonder if a third result is possible. If one of the two stars went supernova, could it eject the other as a hypervelocity star? It seems like the current rotational velocity plus the kick of the explosion might be enough to eject it leaving a single black hole behind.

BG

Agreed about the supernova idea. How likely is it they’d both explode at the same time?

It seems like if the other star wasn’t ejected entirely, that it would be stripped of a huge amount of its mass. Who knows what would happen then?

I’m guessing that likely one of three things would happen: the remaining core gets thrown into a highly elliptical orbit and “quickly” burns out due to lack of fuel, whatever is left gets consumed by the black hole, or no fuel remains at all (the whole thing just gets blasted into a non-fusing cloud of hot gas).

doublemeehhh!!

Maybe because they shared materials and “fuel”, and for that they are going to supernova (without “fuel”) in the same time… for this reason. Because of the link that communicate the two stars and make that the two stars have the same source of energy or combustible. So, the two are going to supernova in the same time, when they depleted all the combustible for their sequence. The “link” between the two stars is a bridge that could maintain both stars in very similar state of the sequence.

Max

Galactus thanks you for your discovery!

Joel Hruska

Finding information on the exact range of sterilizing energy associated with the gamma ray output of collapsing O-Type stars is extremely difficult.

I chose “non-trivial” because “several” was too low and “many” too ambiguous. Non-trivial conveys that you don’t want to be anywhere nearby.

brekinapez

I wonder what it must have been like for any possible lifeforms within the area of effect of GRB 080319B when the wave front passed over their planet? At those dosages, does everything just simply drop dead in its tracks; do they crumple and spend their last few minutes in agony from radiation burns? Does organic material poof into dust and blow away across the now barren ground? The idea of walking down the street and having an invisible wave of energy just sweep across everything and shut it down permanently before you even know it’s happening is kinda freaky.

Actually the atmosphere is quite capable of absorbing unreadable amounts of gamma rays. The main source of destruction caused by a gamma ray burst would be the creation of chemicals that destroy the ozone layer. It would have to be very close (100s of light years) and long duration (10s of seconds) in order to irradiated the surface with a lethal dose of gamma radiation.

No vaporization unless you were orbiting the star that produced the gamma ray burst, but then it wouldn’t be you vaporizing, but your planet. However death via radiation sickness is much slower and much worse than instantaneous vaporization in my opinion.

999

not so rare: I have two of these in my garage.

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